Why can't front panels be aluminium?

[UrSv]

Originally posted by andyjevans
Check Intertechnik>>

I don't speak much German, and when I went through their site looking at the pictures I couldn't find anything - where is it on their site? I was going to make the panels and I wondered how exactly to cut out a large round hole - bigger than all my hole saws. I suppose a jig saw. Mine says up to 8mm aluminium. Any other ideas?

Go to the site. Enter ALU FRONT in the search field (Suchen) and you will find them.

[5th element]

Wilson Benesh (sp??) also use aluminium for front baffles too.

I dont understand whats relevent about the reflective nature of a front baffel. After all 99% of loudspeakers have a solid hard front baffle, be it veneered MDF or corian or metal. The only time you see a baffle with felt or foam is when there is a defraction problem that gives rise to a response error, thus adding the foam helps to reduce this effect.

[simon dart]

Time for me to bang my "Tufnol" drum again!

Most of a small baffle is hole. Stiffness is what you need. Ali is good but 12mm Tufnol is the stuff: much better internal damping than metals and you can machine it with a router yourself.

[rdf]

Using metal for an enclosure can be tricky. I made a small MLTL from 1/4" wall rectangular steel tubing. It has excellent bass but with every vocal confirms why bells are made of steel.
Trying to tame it taught me a lot about constrained layer damping. My next prototype will use a layered front baffle approach, probably three something in the range of 1/16" aluminum and two thin linoluem floor tiles. A single layer of each glued and to the interior walls of the steel line damped resonances immensely (but still not enough.) Stiff, dead and easy to cut.
A another trick that helped a great deal, if you do go metal baffle tap the driver mounting holes and use nylon screws. They transfer much less energy into the baffle.

[GM]

I used to have access to dirt cheap metal electrical control boxes that make excellent monitor sized cabs and got sufficient damping just plastering the insides with cheap self stick floor tiles. Instant constrained layer damping.

GM

[5th element]

Hows about plant pots etc. I was at my local B&Q the other day and looked at the pots. They had some pots that were B&W nautilus shaped. These were about 1" thick out of solid concrete and looked as if they would accomodate a 5 or 6" driver. They were cheapish too about £5 each so for a concrete experiment these would do nicely. Now all i need is some SEAS coax units.

Ill look into Tufnol and corian they sound interesting, especially for an open baffle.

[GM]

Sure! Thor loves his porcelain potted Jordans. Way back when, we used to use round and rectangular concrete or baked clay drain pipe sections left at building sites.

GM

[andyjevans]

Way back when, we used to use round and rectangular concrete or baked clay drain pipe sections left at building sites.>>

Yes - I made some great speakers out of thick concrete 90 degree bends when I lived in Norway - they have thick stuff there for the icy winters, not earthenware. I have some nice earthenware 90 degree bends outside on the balcony as I speak - I won't use them so free to anybody who picks them up. Kensington, London UK - Andy. Looking into Tufnol!

[LaMa]

Originally posted by simon dart
Time for me to bang my "Tufnol" drum again!

Most of a small baffle is hole. Stiffness is what you need. Ali is good but 12mm Tufnol is the stuff: much better internal damping than metals and you can machine it with a router yourself.

I want to try it, but it seems that tufnol is a brand, is it a kind of Fenolformaldehyde bonded with paper or cotton or something??

Because the cotton bonded (brandname tufnol) is way expensive >540 euro for 1 m X 2 m

The paper bonded is about half that price.

edit: only differences is in the static pressure (150 N/mm2 instead of 170 N/mm2) also in moisture content (8% instead of 2.5%) (hard to translate)

[Variac]

Expensive Krell speakers are made from thick aluminum plates.
It has to be pretty thick to work I think, and I assume that they have stuf spread on the inside to damp them.
I think Alu rings a lot less than steel and in say 3/4" thickness won't flex at all on the low notes!